TG-FTIR study on pyrolysis of Enteromorpha prolifera

Pyrolysis of Enteromorpha prolifera was investigated for the first time by using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR). The activation energies of pyrolysis reactions were obtained via the Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose method, respectively. The experimental results showed that the main weight loss of EP occurred between 200 and 350 °C, and almost all the volatiles were evolved in this stage. CO2 was the most prominent non-condensable product, while aldehydes, organic acids, ketones, and ethers were the dominating condensable products. The minor weight loss of EP above 720 °C was possibly caused by the decomposition of calcium carbonate, and it resulted in the formation of CO2, which was further reduced to CO by EP char above 750 °C. In addition, the evolution curves of CH4 and aliphatic C-H exhibited two peaks located between 200 and 600 °C, due to the rupture of methoxy, ethoxy, and methylene. The activation energy of the pyrolysis of EP increased with the increase of conversion rate, and its average value was calculated as 299.84 kJ mol−1 for FWO method and 306.81 kJ mol−1 for KAS method. All of the findings would help further understanding of pyrolysis behavior of EP and its thermo-chemical utilization for fuels and chemicals.